I have the 12.9" iPad Pro that I purchased almost two years ago and just after getting the Inspire 1 Pro I built a frame to hold it and the RC as well as a hood I formed from 5mm flat black foam board. I have shoulder straps to support it and it worked well with the Inspire 1 Pro. The RC hangs below the tablet and is supported even without my hands holding it so I can do other things if needed.
When I got the
P4P about this time last year I decided on a smaller tablet and picked up a 9.7" Samsung Galaxy Tab S2 and built another frame to support it and the RC as well as a foam board hood -- also supported by shoulder straps. The RC hang below just like the other one.
The major problem I've had with the S2 tablet is that I have to futz with it to get the Go 4 app to connect to the RC properly and I generally have to do a tablet power cycle to get it to sync up. Other than that I think the size is just about perfect and a good balance between screen size and portability -- the 12.9" iPad Pro is a bit much with the
P4P but OK with the larger Inspire. If you're going out with the Inspire a larger tablet is the least of your issues.
Brian